Sierra 18-7918 Mercury Oil Filter Sierra high-quality oil filters are designed to meet OEM specifications. Fits 200225250275300350400R HP Verado In-Line 6 cylinder OB. Thread Spec 24mm x 1.5 Anti-Drain-Back Valve Engineered with premium grade materials that will excel in the extreme marine environment Epoxy coated for corrosion resistance Heavy-wall steel canister for further corrosion protection High-efficiency filter media that meets or exceeds the OEs filtration Backed by Sierras industry lea